Introduced: 1970 (U28C) and 1972 (U30CG)
These models are pretty much joined at the hip in terms of their mechanical similarities, so I'm going to save myself a bit of time and cover them both here. Internally, the two models are virtually identical (and share a lot of design similarities with Minitrix's 1970 H12-44 switcher). However, due to their differently sized truck knock-out pins, shells are not interchangeable between the two (not without swapping said pins as well, anyway).
Both are decent enough looking, I suppose. Then again, the bloated handrails and the blocked-out cab windows are a bit of an eyesore (not to mention the open pilots and the truck-mounted Rapido couplers). On the "prototypical accuracy" front, Ron Bearden (noted locomotive expert) informs me that Minitrix's U28C is actually a U30C phase 1b. This assessment is based on really subtle differences in shell detailing (notches, doors, and whatnot). In other words, "Joe Trainset Guy" (EG, guys like me) probably aren't going to lose much sleep over said discrepencies. But anyway, there ya go... something else to worry about (if you're so inclined).
Four out of the six wheels on each truck are geared and provide pickup (no traction tires). The wheels on the innermost axles of each truck are total idlers and comprised of ugly gray styrene (the latter to prevent short-circuiting, or so I'm told). Current is transferred to the motor through the metal chassis itself (IE, no wires). The motor is an open-sided 3-poler, and oddly enough, it is not situated in the center of the chassis. Rather, it's mounted toward the back (thus requiring a long and complex series of driveshafts to reach the forward worm). A non-directional headlight is mounted in the cab end of the chassis. And interestingly enough, a slot for a second bulb is provided on the tail end as well. I don't know if these ever came from the factory with two lights (I've certainly never seen one so-equipped), but adding a second bulb looks to be a relatively simple task.
Performance is not at all bad. In fact, given the era in which these models were produced, I'd say they're pretty darned good runners. Overall, they run smoothly and reasonably quietly at all speeds. Slow speed performance isn't bad, but then again, it's not wowing me either. This same motor was used in Minitrix's H12-44 switcher, and I think it (the motor) is much more up to the task of creeping that smaller locomotive along than it is these 6-axle beasts. The top-end speed is pretty high, but not crazily so. I've certainly seen worse. The chassis is nicely hefty, providing for decent pulling power. The wheel flanges are "old school" crazy-huge, so forget about running one of these on anything like Code-55 track.
Pickup is very good, although I have found that one does have to be vigilant about keeping clean the swiveling brass contacts between the trucks and the chassis - otherwise, performance does tend to get a bit jittery. Also, I've noticed on some of these (now decades old) that the copper contact "stuff" that the swiveling truck contacts rub against (inside the fuel tank) has a tendancy to start peeling off around the edges (thus causing pickup issues through sharp curves).
So, although not without their warts, these are very solid and very respectable locomotives (especially for their era). And I've been told by many an old-time N scaler that this particular chassis/mechanism was "choice one" for repowering projects back in the day (EG, turning a crappy Mehano SD45 into something one could actually operate). Overall, there seems to be a great deal of affection for these locomotives floating around out there in N scale nation.
Note - Starting in 1974, some of the gearing was changed from brass to plastic (namely, the idler gears turned by the worms). Beyond that, these models remained essentially the same throughout their entire production run.
These models were primarily imported by Model Power, although they generally came packaged in the traditional Minitrix "cardboard box" (with nary a mention of Model Power anyplace). Circa 1982, Con-Cor imported undecorated U28C's and U30CG's and sold them in paint schemes not available directly from Minitrix. These were packaged in traditional Con-Cor plastic boxes. These models were ultimately discontinued in 1999 when Minitrix was bought out by Marklin.
Trivia - these shells can reportedly be adapted for use with a Kato U30C/C30-7 chassis, although some minor modifications may be necessary to get a good fit.
To remove the shell, simply pry apart the sides. This will free the shell from the tabs on the chassis.
U28C Reviewed: 8/70 Model Railroader ("The model closely follows the proportions and scale dimensions of the prototype, although a few variations are made to accommodate mechanical requirements of the small model. The body is a one-piece plastic casting with details cast on. The handrails are cast separately and are press-fitted into holes in the body. The frame is a one-piece zinc alloy casting which fills the entire body shell and provides weight for traction. The gearbox housings for the trucks are also cast zinc alloy. The truck sideframes are plastic. The four driven wheels on each truck are metal. The nondriven wheels are plastic; these wheels float to provide lateral motion. All wheels scale 42" in diameter with .035"-deep flanges, giving an overall diameter of 55". A small five-pole DC motor is ingeniously mounted in the zinc frame. It drives four axles, two per truck... Electrical connections to the motor are made through wipers on each truck. These ride on a PC board concealed by the snap-on plastic fuel tank. Headlight and number boards in the short-hood end are illuminated. Rapido-type plastic automatic couplers are attached to each truck. Our test sample ran smoothly and quietly. Speed control was good through all voltages... The model will haul 38 to 40 freight caars... The minimum scale running and starting speed is high... The model is available in SF, PC, NP and L&N color and lettering schemes. Price: $20")